Off-grid electrical system with battery storage
using a charge regulator
Typical off-grid electrical system with battery
storage using a self-regulating module
Typical Photovoltaic system coupled to the public electricity grid
1 solar modules
2 inverter
3 utility meter (electricity generated)
4 utility grid
5 utility meter (electricity drawn)
6 appliances
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There are many different applications for
photovoltaic solar energy systems. This guide
describes some of the most important typical
uses as representative examples.
Off-grid electrical system with battery stor-
age using a charge regulator
Solar power systems are frequently used to
supply electrical power to technical equip-
ment, remote cottages and hunting cabins,
camping vehicles and boats. In such systems,
the photovoltaic system charges a storage
battery via a charging regulator. The charg-
ing regulator controls the charging proc-
ess in order to protect the battery against
overcharging and ensure long battery life. If
necessary, an inverter can be used to provide
electrical power from the storage battery to
equipment operating at the normal mains
voltage.
Off-grid electrical system with battery stor-
age using a self-regulating module
When a self-regulating module is used, it is
not necessary to use a charging regulator.
The charging current provided by the self-
regulating module depends on the charge
state of the battery and decreases as the
battery voltage increases. This means that
during daylight hours, the charging current
automatically adjusts to suit the charge state
of the battery and the power consumption of
the connected loads.
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When using a self-regulating
module, make sure there is
sufficient battery capacity.
In the dark a small current could flow from
the battery and through the module. This
can reduce the state of charge of the battery
during the night. To eliminate this reverse
current, connect a “blocking diode” in series
between the solar module and the battery.
Use a diode that is specified for a current
that is at least 1.5 times more than the
maximum current generated by the module.
Mount the diode in such a way that allows
for proper cooling of this device. Please
check with your dealer for an appropriate
diode type.
Grid-connected electrical system
For this purpose, the electrical energy
generated by the solar power system
is supplied to the public electricity grid.
The structure and dimensioning of the system
vary from system to system. Usually, several
modules are connected in series to form a
block, and several blocks are connected in
parallel to a network inverter that links the
photovoltaic solar power system to the public
electricity grid. The amount of power fed into
the public electricity grid can be measured
using a supplementary meter. See “Compari-
son of series and parallel wiring“, page 8.
The amount of compensation paid for the
power fed into the public electricity grid de-
pends on contractual agreements with elec-
tricity companies and statutory provisions.
A permit is always required for any system
coupled to the public electricity grid, and
such a system must be formally approved
and accepted by an authorised expert.
Electrical Installation
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